Preincubation of guinea pig heart ventricle sarcolemmal membranes with exogenous protein kinase, cyclic AMP, or isoproterenol enhanced calcium accumulation and increased Ca2+-dependent ATPase activity.
Does preincubation with protein kinase, cyclic AMP, or isoproterenol increase calcium accumulation in guinea pig heart sarcolemmal membranes?
Protein kinase enhances calcium accumulation and Ca2+-dependent ATPase activity in cardiac sarcolemmal membranes, suggesting a mechanism for regulating cardiac contractility.
Sarcolemmal membranes isolated from guinea pig heart ventricles contained an ATP-dependent calcium-sequestering activity. Sarcolemmal calcium accumulation but not binding was enhanced by preincubation of membranes with exogenous protein kinase, with cyclic AMP, or with isoproterenol. Protein kinase (EC 2.7.1.37) increased the V of Ca2+ accumulation by sarcolemma without any significant effect on the affinity for Ca2+. The endogenous protein kinase activity present in isolated sarcolemma affected membrane phosphorylation. Cyclic AMP increased the endogenous kinase activity modestly, whereas histone increased it significantly. Exogenous protein kinase also catalyzed phosphorylation of these membranes. Endogenous and exogenous kinase-catalyzed phosphorylation of sarcolemma was hydroxylamine-insensitive. Ca2+-dependent ATPase (EC 3.6.1.3) (extra ATPase) activity of sarcolemma was also increased by protein kinase.
Sulakhe et al. (1976) studied this question. Exogenous protein kinase, cyclic AMP, or isoproterenol was evaluated on Sarcolemmal calcium accumulation and membrane phosphorylation. Preincubation of guinea pig heart ventricle sarcolemmal membranes with exogenous protein kinase, cyclic AMP, or isoproterenol enhanced calcium accumulation and increased Ca2+-dependent ATPase activity.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: